Detergometer



March 14, 1961 MI. E. LANE ErM.

DETERGOMETER 7 Filed Aug. '7, 1957 mw m INVEN TOR. V/V/fQ p Z5? 10/76, e/a/ Unit W s Patten Q.

DETERGOMETER Filed Aug. 7, 1951, Ser. No. 676,906

1 Claim. 01. 73-53 (Granted under Title '35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The invention relates to detergometers and, more in particular, to detergometers of the type used in research laboratories for determining the eifects of various detergents.

Although both manufacturers and consumers of the many diiferent detergent products have utilized a wide variety of tests to determine the effect of their detergents, it apparently is a fact that the prior art does not oflfer any single apparatus capable of providing such reliable and reproducible cleaning test results as to permit standardization of their use. The principal-difficulty is due to the many variables which if not precisely controlled are capable of materially aflecting the test results so as to provide data which is far from reliable. For example,

even though a sample is evenly exposed for an exact period of time to a cleaning solution of a particular concentration, the actual effect of the solution or detergent still will vary considerably with variations of temperature or variations of impact pressure. In other instances, even though impact pressure and temperature might be maintained at a constant, unreliable data nevertheless frequently results because of the fact that the sample was not equallyexposed to all portions of'the detergent spray and therefore because certain portions of the spray might have more impact pressure than others, the over-all cleaning effect on one sample might be substantially diflerent from that on another. Other difliculties whichv arise involve the possibility that the solution being applied might vary its concentration from time to time because of incomplete mixing.

It is therefore an object of the present invention to provide detergometer apparatus in which all of the variables capable of aifecting the cleaning capacity of a detergent are subjected to such close control as to eflectively minimize their over-all effect.

A further object is to provide apparatus in accordance with the last object which is relatively simple, inexpensive, compact and quickly and easily operated.

According to the present invention, the detergometer basically includes a mixing tank, a spray chamber, a pump and a controlled circulating system. The detergent composition is mixed in the mixing tank and, further, the temperature of the mixture is carefully and constantly controlled by introducing into it independent sources of heated and unheated fluid. The sample to be treated is mounted in the spray chamber beneath a spray nozzle,

and the pump, of course, is used to deliver the temperature-controlled, thoroughly mixed solution from the mixing tank to the spray nozzle. In the circulating system, the conduit coupling the pump to the spray nozzle preferably is provided with valve means by which the nozzle pressure can be varied independentlyof the pump pressure and further, both temperature and pressure means are conveniently mounted at the nozzle to assure close control of these two factors.

-Mqre specifically, a preferred embodiment of the invention employs a mixing tank disposed in a vertical position and formed with bell-shaped bottom end wall provided with an opening. A funnel most suitably is closely fitted into the top of the tank and above the funnel preferably is mounted a hopper in which the solution ingredients initially may be mixed prior to introduction through the funnel into the mixing tank.

Most suitably, fluid from both the independent sources of heated and unheated fluid selectively are introduced into the tank through its bottom opening. Such being the arrangement, it can be appreciated that a solution of desired ingredients can be introduced through the funnel into the mixing tank and then the heated or unheated fluid, such as air or steam, selectively introduced not only for the purpose of achieving a precise solution temperature, but also to assure intimate mixing and continued agitation of the mixture. The mixing action is produced by the bubbling action of the gas as it is admitted into the tank and preferably this action is improved by the shape of the bottom and by admitting the gases into its central portion.

To circulate the mixture to the spray nozzle, the intake of the pump is coupled to the bottom of the tank and, as already indicated, the pressure in the pump delivery line is independently valve-controlled, Another feature of importance is the manner inwhich the sample is mounted in the spray chamber. Thus, the sample preferably is mounted beneath the spray on a sample platform that is reciprocably driven transversely to and fro beneath the spray while, simultaneously, the platform also is rotated. The purposeof such reciprocable and rotary movement is to assure equal exposure of all surfaces of the sample to all portions of the spray.

Generally considered, it will be appreciated that such an apparatus permits such close control of temperature, pressure, equalization of impact, concentration of solution and time of contact as to assure reproducible results.

The preferred embodiment of the invention is illustrated in the accompanying single drawing which somewhat schematically illustrates the arrangement and interconnections of the various components.

Referring to the drawing, the apparatus generally includes such components as the mixing tank 1 disposed beneath a hopper 2, a spray chamber 3, and a motor driven pump 4 for delivering the mixture in tank 1 to the spray chamber.

As to the mixing tank, it is formed, preferably, with bell-shaped top and bottom end walls 6 and 7, and mounted in the central portion of the top wall 6 is a funnel 8 disposed directly beneath a discharge pipe 9 of hopper 2, this discharge pipe being provided with a conventional shut-01f valve 10'. Hopper 2, in turn, preferably is formed as an open-top container and a suitable agitator or mixer 12 is carried at the open top to initially mix ingredients as they are poured into the container. Also, the container mounts a level gauge 13 which may be indexed in liters to facilitate the initial mixing of the ingredients.

Temperature control for the mixture is accomplished by the use of separate pressured sources of heated and unheated fluid, such as a source of steam admitted through a conduit 14 and a source of air admitted through conduit 16, and selective use of one or the other is permittedly any conventional valve arrangement. Also, both conduits l4 and 16 preferably lead into a common cond'uit 17 which in turn is coupled into an opening provided centrally in bottom end wall 7 of mixing tank 1. As a result, a solution can be initially admitted into mixing tank 1 and the temperature of the solution within this tank controlled by admitting either steam or air through common conduit 17.

Not only is a particular desired temperature achievable in this manner, but also the admission of the air or gas produces a bubbling action within the mixing tank which maintains the solution mixture in an agitated condition until actual application within spray chamber 3 is desired. As will be appreciated, the shape of the mixing tank permits the bubbling action to affect all portions of the solution within the tank so that an intimate mixture is achieved. Preferably, a temperature gauge 18 also is mounted in the bottom of tank 1.

As has been previously expressed, motor driven pump 4 is used to deliver the mixture within tank 1 to the spray chamber and to accomplish. this purpose, common conduit 17 is connected by a short length of pipe 19 to the intake side of this pump. Also, a manually controlled valve 21 is mounted in pipe length 19 so as to selectively communicate the pump pressure with the mixing tank.

The discharge of the pump is delivered to the spray chamber through another conduit 22 which terminates in a spray nozzle 23 projecting downwardly through the top wall of the spray chamber 2, and, as will be explained in more detail, this conduit mounts various elements enabling temperature and pressure control at the nozzle. Thus, conduit 22 mounts a pressure gauge 24 and a temperature gauge 26 as well as a threeway valve 27. As may be noted, valve 27 is provided with a handoperated lever which may be thrown to one position to admit the detergent solution under pressure to the spray nozzle or to another position to direct any detergent within conduit 22 into a drain pipe 28.

Also, to control the spray nozzle pressure independently of the pump pressure, a by-pass line 29 short circuits the flow through conduit 22 back into common conduit 17 for return to the intake side of the pump and suitable manually controlled valves 31, 32 and 33 are mounted in these lines to permit the desired action. Thus, by partially closing valve 31 and partially opening valve 32 it is possible to by-pass a portion of the flow back to the pump thereby reducing the pressure Within conduit 22 and consequently at nozzle 23. Similarly, valve 33, which is mounted in common conduit 17, can be opened or closed to directly affect the pull of the pump intake on the mixing tank solution. As will be appreciated, these three valves can be manipulated in any desired manner to achieve extremely close control of the nozzle pressure.

Another quite important feature that has been broadly contemplated is the movable mounting of the sample beneath the nozzle spray. Thus, as will be noted in the drawing, the side walls of the spray chamber support a traverse rod 36 preferably provided with inter-connected rightand left-handed square-channeled threads 37 and 38 such as permit a self-reversing action for any member movably mounted on the threads. As also may be noted, traverse rod 36 is rotatably driven by a rheostat-controlled motor 41 and the rod mounts a collar 42 provided with a single pin (not shown) that projects into the threads so as to produce self-reversing reciprocating movement of the collar as the rod is driven. Also, collar 42 mounts a sample platform 43 on an upwardly projecting shaft 44 and, most suitably, the sample platform carries a plurality of spring clips for securing the actual samples.

It further is desirable to rotate the samples beneath the spray as well as to reciprocate them and the rotation is achieved by means of a rack 46 in which is engaged a pinion 47 that, as seen, is suitably splined to 01' otherwise secured on the lower end of shaft 44. Consequently, samples mounted on platform 43 are carried by the reciprocating and rotating action of the platform into all portions of the spray so that the samples are exposed equally to all portions of the spray. The result is that variations in impact pressure due to possible variations in various portions of the spray are effectively minimized. Most suitably, the spray nozzle is chosen and positioned so as to direct its spray substantially over the width of the platform traverse although this factor is subject to the desires of the operator. As a typical example, a spray chamber can be provided that is approximately 36 inches high, 24 inches deep and 30 inches long, and in such a chamber may be mounted a nozzle having a inch full jet 45 cone positioned 15 inches directly above the center of the threaded traverse rod. Of course, such dimensions are variable in accordince with design specifications and the particular purpose for which the apparatus itself is to be used.

A further important feature of the invention resides in particular means to assure precise timing of the contact of the spray with the sample and such timing means may be provided quite simply by the use of a commercially-available Microflex timer 48 connected between the power source and the pump motor. A further refinement of the invention which can be coordinated with the spray time interval is a rheostat-controlled motor 41 by means of which the reciprocation and rotation rate of the platform can be closely adjusted in accordance with any particular desire.

The operation of the apparatus has been partially described'but can be clarified by specifically considering the mixture and application of a particular solution. Thus, assuming the use of a mixing tank having a capacity of 30 liters which is the capacity of a tank having the dimensions previously described, a 75 centigrade fresh water solution most suitably is obtained first by introducing approximately 15 liters of tap water into the mixing tank and then admitting steam through conduit 14 in sufficient quantity to obtain a reading on the tank of centigradc. Next, 240 grams of a desired additive may be dissolved in water by mixing the solution in hopper 2. When mixed, this additive solution is poured through the funnel into the mixing tank and steam and water then carefully added until the tank contains the desired 30 liters of 0.8% solution at 77 centigrade. The 77 centigrade temperature at the mixing tank allows a 21 centigrade temperature drop between the tank and the spray nozzle, although as will be obvious, this temperature drop will vary and therefore should be regulated according to existing conditions.

Before any samples are sprayed with this particular solution, a sufficient amount of the solution is run through the apparatus to establish a steady state in which the thermometer at the nozzle registers the required temperature. Also, during this pre-run, the several valves described are manipulated to achieve the desired pressure which can be read on the pressure gauge at the nozzle. In most operations at least 4 samples can be subjected to the spray at one time and in a typical case these samples may be passed 7 times beneath the spray nozzle within a 30 seconds spraying period, which period is measured by the Microflex timer previously described.

In other operations it may be desired to apply a 20 centigrade solution, although such a solution is prepared in a similar manner except that air instead of steam is bubbled through the solution to insure intimate mixing. In fact, it is within the present concept to also employ 1'e frigeration if research is being directed toward the effect of low temperature solutions.

A number of modifications and refinements within the intended scope of the invention will be somewhat apparmeans for controlling pressures or for producing the desired movement of samples beneath the spray are possible.

As to refinements, it is appropriate to employ a level gauge on the mixing tank to facilitate mixing, although such a gauge has not previously been described. Also, the doors of the spraying chamber most suitably can be made from some transparent material such as permits observation of conditions within the chamber and, to further facilitate observation, the chamber can mount a suitable light. Other modifications and refinements can be employed depending upon the particular use to which the apparatus is put and it again should be emphasized that the present description has been solely with reference to a preferred embodiment.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that Within the scope of the appended claim the invention may be practiced otherwise than as specifically described.

I olaim:

A detergometer for scientifically testing the eifectiveness of various detergents comprising a detergent solution, a mixing system including a bell ended tank for holding a solution charge and provided with a two way connection at the bottom of said bell and control means for selectively communicating with steam and air sources for mixing and varying the temperature of said charge and draining said tank, a pressure temperature control system including a pump and by pass re-circulating system for selectively mixing air, steam and the solution charge in correct proportions and at a selected temperature and pressure, a spray chamber, a spray nozzle and a horizontal sample platform housed within said chamber, said spray nozzle connected to said control system and positoned for directing the spray solution stream vertically downward and normal to said horizontal sample platform, said platform being mounted on a vertical shaft and rotatively supported in the follower of a traverse motion, whereby the platform face is reciprocated across said spray stream, a pinion keyed to said vertical shaft and in driving contact with a rack mounted parallel with said traverse for rotating said platform as it reciprocates across said spray stream, and means for regulating the rate of travel and rotation of said sample platform.

References Cited in the file of this patent UNITED STATES PATENTS 2,372,533 Torbett Mar. 27, 1945 2,389,488 Dailey Nov. 20, 1945 2,684,595 Wollner et al July 27, 1954 2,729,098 MacKenzie et a l Jan. 3, 1956 

